1. Field of the Invention
The present invention relates to a lamp. Particularly, it relates to a lamp having a planar light-emitting source. This invention has a planar light-emitting function with better lighting efficiency. The planar lighting is evenly distributed without shadow. Its energy consumption and heat generation is low. The product's life is prolonged. Its volume is small and it is portable.
2. Description of the Prior Art
There are many kinds of traditional desk lamp. But, most of them use the electric bulb as the main lighting source.
One of them directly utilizes the light emitting diodes (or briefly called LED) as its lighting source 12. For example, as shown in FIGS. 11 and 12, it is a traffic light 92 having LED array. In this LED array, there is a plurality of point-shaped light source 921.
However, the traditional device has the following disadvantages.
[1] The lighting efficiency for point-shaped lighting source is poor. If one person just directly utilizes the LED as the light source, it can reduce the cost, but such point-shaped lighting source cannot provide enough brightness. So, the lighting efficiency is poor.
[2] There is a serious shadow problem. If someone uses the LED array as the light source, even though its brightness can be raised, the light still is not uniformly distributed. Also, the shadow problem among any adjacent LEDs is unavoidable.
[3] The energy consumption is high, its life is shorter, and it has heating problem. The traditional electric bulb's energy consumption is high. It also generates heat. After the long term of use, it is easy to be burned out. Thus, the product's life is relative short. In addition, the heating problem is another disadvantage.
[4] The cost is high and it causes the environmental problem. Because the traditional electric bulb's life is shorter, its overall lighting cost is higher. Besides, a traditional fluorescent tube contains mercury (Hg). Mercury is harmful for our environment.
[5] The volume is large and it is not easy to carry. The traditional lamp has larger volume so it will occupy more space. It is not easy to put into a pocket of clothes or into a bag. Thus, it is not easy to carry.